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i (No Model.) I 5 Sheets'-Sheet 1.

' H. T. GILES.

. BALANCED SLIDE VALVE.

No. 373,182. Patentd Nov. 15, 188.7.

(No Modem v 5 Shets'Sheet 2. H. T. GILES. BALANG'E'DSLIDE VALVE.

Patented Nov. 15, 1887.

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(No Model.) 5 Shets--Sheet a.

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BALANCED SLIDE VALVE. No. 373,182. v Paflzemted Nov. 15-, 1887.

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- (No Model.) 5 Sheets-'Sheet 4.

v H. T. GILES. V BALANCED SLIDE VALVE.

No. 373,182. Patented Nov. 1-5, 1887.

(No Model.) 5 Sheets-Sheet 5.

H. '1. GILES.

BALANCED SLIDE No. 373,182. Patented Nov. 1'5 1887.

QXWm/eoow gmoemtoz UNI'IED. STATES PATENT OFFICE.

HENRY T. GILES, OF WASHINGTON, DISTRICT OF COLUMBIA, ASSIGNOR OFONE-FOURTH TO ALBERT OOWELL, OF SAME PLACE.

BALANCED SLIDE-VALVE.

SPECIFICATION forming part of Letters Patent No. 373,182, dated November15, 1887.

- Application filed October 20, 1886. Serial No. 216,7 2. (No model.)

To all whom it may concern:

. Be it known that I, HENRY T.G1LEs, a citizen of the United States,residing at Washington, in the District of Columbia, have in 5 ventedcertain new and useful'lmprovements in Balanced Slide-Valves; and I dohereby declare the following to be a full, clear, and exact descriptionof theinventiomsuch as will enable.

. others skilled in the art to which it appertains to make and use thesame. 7

- This in vention relates to the slide-valves of steam-engines; and itconsists in mechanism and construction for balancing the same. In thecase of the usual slide-valve used inmost engines the outer side of thevalve is acted upon by the steam in the steam-chest, which presses thevalve on its seat with great force. This not only renders the valvedifficult to 0p erate, but also wears the valve and its seat veryrapidly; and in cases where these valves are used in verticalengines-such as marine engines, for exampleth'e weight of the valve andits connections, which is very great in large engines-has to be borne bythevalve- 2 5 rod and its connections, subjecting their joints to rapidwear, requiring expenditure of power for the operation of the valve, andnecessitating a heavy valve-rod and connections. 7

I The present invention consists, primarily,'in 3o balancing the valveagainst the steam-pressure in the steam-chest in all kinds of enginesusing a slide-valve, and, secondarily, in balancing the Weight of thevalve in upright engines.

Many constructions of slide-valveshave been devised to balance the sameagainst the steampressure-such as, for example, fitting the valve withan elastic balance-plate movable therewith, which slides beneath a fixedbal- '0 ance-plate secured to the steam-chest; but, so

far as I am aware, none of. them have practically succeeded in perfectlybalancing .the valve. The main difficulty lies in providing againstcurrents in the steam and back-pressure, which, in case the valve isperfectly balanced, ornearly so, lifts the valve from the seat, thusadmitting the live steam into both ends of the cylinder and into theexhaust. In

' such an emergency, which is of frequent oocurrence where the valvesare nearly perfectly v balanced, it is necessary to cut off the steamentirely before the valve will again reseat itself. Therefore it hasbeen in practice only attempted to partially balance the, valve. Now, inthe present invention, the opposite areas of the valve are made exactlyequal, or approximately so, and the valve is constructed so that thisequality will be preserved in all positions of the valve, and animportant feature of the invention consists in the means for holding thevalve against back-pressure. The present invention is more particularlyadapted to valves of the Allen type, wherein double entrance-ports inthe valve are provided, and theinvention itself is a development ofthose balanced valves which have a sliding balance-plate carried by thevalve, operating in connection with a fixed balanceplate secured to thesteam-chest cover.

Theinvention also includes an improved arrangement of the ports, whichassists in the balancing of the valve, and means for lubricating thebearing-surface of the sliding balanceplate.

In the accompanying drawings, Figure 1 is a longitudinal central sectionof the valve and steam-chest. Fig. 2 is, a cross-section of the valve.Fig.3 is a plan View of the valve and valve-seat, one half of the figureshowing the upper side of the valve, the other half showing thevalve-seat. Fig. 4 is a view of the sliding balance-plate, showing theupper and lower sides thereof. Fig. 5 is a view of the valve, showing itin a different position from that shown in Fig. 1. Fig. 6 is a sectionalview of 8 5 the valve-cap of the balancingcylinder. Fig.

7 are details of the packing-strips, and Fig. 8 is aview of amodificaiton.

A is a portion of the steam-cylinder; B B,

the side walls of the steam-chest; O, the re- 0 I movable top plate ofthe steanrchest; a, the exhaust-steam port, and b b the maininduction-steam passages.

. Dis the slide-valve, E is the valve-rod, and

c is the valve-seat or surface of the cylinder 5 onwhich the valve restsand slides.

F is the stationary balance-plate, adj ustably secured to the-top plateof the valve-chest for taking up wear by set-screws d d.

The valve proper, D, only occupies a portion of the space between theseat 0 and the balanceplate F, a space or chamber, G, being left betweenthem. The exhaust opening or passage e of the valve is entirely open tothis chamber.

H is the sliding balance-plate, which slides with the valve. Thissliding plate is held in contact with thestationary balance-plate bymeans of coiled springs f f, which are carried by the valve andsupported by pins or studs 9 g on the valve.

In order to form a steam-tight connection between the valve and slidingbalance-plate, so as to render impossible communication be tween thelive steam in the steamchest and the exhaust-chamber G, the valve isprovided with a perpendicular rim, h, projecting toward thebalance-plate and beveled on itsinner face, i. The sliding balance-plateH is also provided with a rim, j, projecting toward the valve andoverreaching and inclosed by the rim h on the valve. Each of the rims hjis straight in outline, and four straight spaces are formed betweenthem. These spaces are filled with four packing-strips, I I, which forma steam-tight joint between the two rims hj. Each strip has one beveledface, 7c, corresponding with the beveled face 6 of the rim h,so that anywear between the packing-strips and the rims may be taken up. To holdthese packingstrips firmly against their seats when the steam is cut offcoiled springs Z Z are used, the steam'pressure in the steam-chestholding the strips in place when the steam is on. These springs are heldin recesses m, formed in an overhanging and projecting flange, J, formedon the sliding balance-plate, and which bear against the outer widersurfaces of the packing-strips. These packing-strips not only form asteam-tight joint, but prevent any move ment between the valve and thesliding ba1- ance-plate, so that the valve and plate move together.

In addition to the packing-strips I I, there are also used thinsheet-metal auxiliary packing-strips, I I, which are placed between thebeveled faces 6 it. These strips, which are only used in case thepacking-strips I are made of metal, assist in making the jointsteam-tight, and can easily be replaced by thicker ones to take up wear.

In the valve shown in the principal figures of the drawings the passagesb I), leading to the steam-cylinder, have each two ports, n n and o 0",respectively, and the valve is so constructed that both ports on thesteam side are open simultaneously, so as to admit the steam in doublequantities to the cylinder on the first opening of the ports; The valveshown is also constructed so that double openings to the exhaust areprovided. In the present valve the arrangement of the ports in the valveare utilized to assist in balancing the valve. The outside ports, a o,are uncovered by the movement of the valve, so that they have directcommunication with the steamchest. The travel of the valve is, however,not sufiicient to directly uncover the inner ports, a 0, so thatlive-steam passages p q are formed in the valve to establishcommunication at the proper times between the said ports and thesteam-chest. These passages 11 q extend through the end walls of thevalve, and are at all times filled with live steam. Between theport-openingsp q of the passages p q and the ends of the valve arelocated the auxiliary exhaust ports and passages r 8. These ports arealways open to the exhaustchamber G. These exhaust-passages r s arearranged to coincide with the ports n 0', respectively, the ports a 0being uncovered directly to the exhaust by the movement of the valve.

It is desirable that the several port-openings p q a" .9 should have anarea at least equal to their respective ports a" o n 0, and in order topermit the passages 11 q to pass the passages 1' s the latter arecontracted in width as they approach the chamber G, as indicated indotted lines in Fig. 2, and at the same time widened in the otherdirection, as shown in Fig. 1. Each live-steam passage 19 q branches andpasses on both sides. of the passages r s, having two openings, 25 t, inthe ends of the valve, as shown in Fig. 2.

The operation will be readily under-stood.

At the instant that the port n is uncovered by the valve the port 19opens the port M, and when the valve uncovers port 0 to the exhaust,port 8 also opens the port 0 to the exhaust, and vice versa on themovement of the valve in the opposite direction. Both passagesp q, itwill be thus seen, are always filled with live steam, and they thusbalance the valve to the extent of the area of the ports To lubricatethe sliding balance-plate its upper or bearing surface is provided withlongitudinal grooves u u, and the stationary balance-plate is recessedon its inner surface, forming shoulders or ledges v v. The widths of thebearing-surfaces of the sliding and stationary balance-plates are soproportioned to the travel of the valve that at the extreme movement ofthe valve in one direction the outer groove u passes beyond theedgew ofthe balance-plate, and when the valve is at its extreme travel in theopposite direction the inner groove 11. passes beyond the inner ledge aof the stationary balance-plate. When the grooves u "u are thus freefrom the stationary balance-plate, they fill with steam and oil,

which constitute the lubricant.

In proportioning the valve and the sliding balance-plate the design isto make their areas exactly equal, or nearly so, since it is designed tohave the valve perfectly balanced. In the valve shown the areas of theports 1) q are to be deducted from the valve-area, since they assist inbalancing the valve.

Slide-valves are usually made the full width of the steam-chest. In myconstruction the IIO . I W i balance-plate must be narrower than thevalve, so as to provide for the reception ofthe back-pressure bars,hereinafter described. In order, then, to render the areas equal, theother or lengthwisedimension of the sliding balance-plate must begreater than that of the valve. As has been before described, thebalance-plate is held'within projections h h on the-valve, and in orderthat these projections on the ends of the valve may be extended beyondthe bearing-surface of the valve,the valve on its side next thebalance-plate is formed with outwardly-projecting flanges K K on itsends,whereby the lengthwise dimensionofthe sliding balance-plate isincreased without increasing the area of the bearingsurface of thevalve. In this manner it is possible to balance the valve as nearlyperfect as can be.

When theslidiug balance-plate H, during the travel of the valve, passesbeyond the .edges 10 o of the stationary balance-plate, as it must do inorder to lubricate the balance-plates,the balance of the valve wouldnaturally be destroyed. The parts are, however, so constructed as toprovide against this. The area of the exhaust-port a in thesteam-cylinder is so constructed that when the sliding balanceplatereaches the shoulders v othe edges ofthe valve at the opening 0 reachthe'edges x m of the exhaust-port. At opposite ends of the steam-chestthe outer surface of the steam-cylinde r is cut away, as shown, leavingledges or shoulders 31 y at the ends of the valve-seat. The valvetravels beyond these ledges y y in its movement to an amount exactlyequal to the travel of the sliding balance-plate beyond the edges'w w ofthe stationary balance-plate. In this way the valve is at all times asperfectly balanced as the varying condition of the steampressure willallow. As stated at the beginning ofthis specification, there are,however, practical objections to a perfectly-balanced valve, since sucha valve will be lifted from its seat by back-pressu re. The presentinvention includes means for preventing this.

On the sides of the valve the rims h h are cut in, leaving flat outersurfaces, Z Z, on the valve. In co-operation with these surfaces ZZ arelongitudinal back-pressure bars L L. These bars extend lengthwise thewholelength of the steam-chest, and are nominally held out of contactwith'the surfaces 2 2 by springs M M. seated incupped projections N N inthe corners of the steamchest. The back-pressure bars are brought withinproper distance of the valve by means of set screws 0 O.passing throughthe cover of the steam-chest. By this arrangement none of the weight ofthe back-pressure bars is borne by the valve; but the back-pressure barsmay be brought so close to the valve that-while they do not interferewith the free movement of the valve they will effectually prevent thevalve being lifted from its seat. 7

In order that the valve may be easily connected or disconnected with thevalve-rod E cable to any steam-engine, whether vertical or horizontal.When used in upright engines, it is also. contemplated to balance theweight of the valve and its connections. To this end there is providedon the upper end of the steam-chest a balancing-cylinder, S,which hascommunication with the steam-chest by steamports a a. In this cylinderis a piston, T, which is connected to the valve by the pistonrod IL Thisrod is preferably connected to the valve by means of a lip, P, and aslot, Q, on the valve, and T-head R. on the rod, the same as thevalve-rod E. The steam-pressure in the steam-chest,.acting against theunder surface of the piston, exerts a force to lift the piston, and withit the valve, which counteracts the weight of the valve and itsconnections. The area of the piston will be determined by the weight ofthe valve and its connections and the steam-pressure to be used in thesteam-chest. When the pressure falls below the normal, the valve, unlessotherwise provided, would not be balanced, and when the pressure risesabove the normal the valve would be overbalanced. To equalize thebalancing eflect ofthe piston under varying steampressure, the upperouter end of the cylinder is open and covered with a movable andremovable cap, V. This cap has a circular guideflange, W, which embracesthe exterior surface of the cylinder. Each half of this flange isprovided with oneopen inclined slot, X, and two vertical slots, Y Z,ofdiflerent heights. Near the juncture of the flange and cap the flangeis provided with aseries of perforations or apertures, e e. The severalslots X Y Z co-operate with pins or lugs A A on the exterior of thecylinder. When the lugs are held in the inclined slots X, the cap isheld immovable on the cylinder-,with the apertures e e constantlyclosed. When the lugs are held in theshort slots y, the cap will beraised and'the apertures will be constantly open to the interior of thecylinder above the piston; and when the lugs are held in the long slotsthen the cap can move up and down, unclosing the apertures. WVhen thepressure is normal in the steam-chest, the cap is so arranged that theapertures will be always open. When, now, the pressure falls below thenormal, the cap is turned, so that the lugs enter the long slots, andthe cap can move up and down, acting as a valve. The movement of thepiston will soon pump out the air in the upper part of the cylinder,leaving a partial vacuum, which is equivalent toqraising theboiler-pressure. If, however, the boiler-pressure is too light, the lugsarecaused to enter the inclined slots, and the cap is held down with theapertures closed. The inclosed air in the upper part of the cylinderthus offers resistance against the piston and partially counterbalancesthe steam-pressure.

The balancing cylinder need not be a separate piece, as shown, but maybe formed directly on the end of the steam-chest, with its whole areadirectly open to the steam-chest. It is only essential that a chamber beformed in which the piston may work. This cylinder S need not be inconnection with the steam of the steam-chest, but may he worked entirelyby atmospheric pressure. In that case a permanent vacuum would he formedabovethe piston, and the cylinder below the piston would be open to theatmosphere, as by apertures (1 (L2, as indicated in dotted line inFig. 1. The piston in this case would be larger than if acted upon bythe steam-pressure.

In Fig.8 is shown an ordinary D-valve provided with thepresentimprovements so far as they are applicable thereto This valve, asit is usually formed, has a face, D, largerin area than the body I).Surrounding the body D and resting on the upper side of the projectingface D is the yoke E of the valve-rod, which can he lifted off thevalve. The necessity of separating the valve from the yoke prevents theemployment of the flanges K K. Accordingly, to make the balance-plate Hlarge enough, the tiangej on the balance-plate embraces thebody D" ofthe valve. The inner face of the flangej carries thehevel i, and thepacking-strips I are inserted with their small ends upward instead ofdownward. The packingstrips will be held upward ordinarily by thesteam-pressure; but in case the latter is cut off the retaining-springsZ Zare used. The holding-sockets m m for these springs are in this casedrilled in the yoke E. Since the back-pressure bars cannot be used withthis valve, the area of the balance-plate is made less than that of thevalve, so that the valve cannot be lifted from its seat by ordinarybackpressure. So, also, in lubricating the balanceplates, the plate Hmoves farther beyond the edge w than the valve moves beyond the ledge 3On one end the rim j is shown cut away on its inner face, at g, toindicate how it may be habbitted to take up wear between the rim and thestrips I, and to save dressing down. This figure illustrates how many ofthe foregoing improvements can be applied directly to the ordinaryvalves in common use.

I claim as my invention 1. A slide-valve and a sliding plate carriedthereby, a rim on said slide-valve, and a rim on said slidingbalance'plate, one of said rims extending beyond and inclosing theother, in

combination with packing-strips between the two rims, substantially asset forth.

2. Projecting rims on a slide-valve and a sliding balance plate,respectively, one of said rims having a beveled face, in combinationwith packing-strips located between said rims, each strip having abeveled face in contact with the beveled face on the rim,substantiallyas set forth.

3. A slide-valve and a sliding balance-plate carried thereby andprojecting inclosing-rims on said valve and balance plate, incombination with packing-strips between said rims and springs forholding said strips against their seats. 7

4. Rims on aslide-valve and sliding balanceplate, respectively, one ofsaid rims having a beveled face, in combination with sheet-metalauxiliary packingstrips next said beveled face and packing-strips havinga beveled face located between said rims and seated against saidauxiliary packing-strips, substantially as set forth.

5. The combination of a slide-valve and a stationary balanceplate, witha sliding balanceplate carried by the valve and in contact with saidstationary plate, said sliding plate having lubricating-grooves on itsface next the stationary balance-plate, said sliding balanceplate beingcarried by the travel of the valve on both the steam and exhaust sidesbeyond the edges of the stationary plate, substantially as set forth,whereby the lubricating-grooves are opened to the steam.

6. A stationary balance-plate and a sliding balance-plate carried by aslide-valve, said sliding plate having lubricatinggrooves on its facenext the stationary plate, said grooves heing carried by the travel ofthe valve beyond the edges of the stationary plate, in combination withthe s1ide-valve and its seat, said valve being carried beyond its seatsimultaneously with and to the same extent as the sliding balance-plateis carried beyond the stationary plate, substantially as set forth.

7. A slide-valve'having main exhaust-passage e, outer exhaust-passages,1* s, in constant communication with said exhaust e, andinductionpassages p q between said main exhauste and outer exhausts, r8, said passages 12 q branching on either side of said exhausts 1' s,and each having double openings t t on the end of the valve.substantially as set forth.

8. A balanced slide-valve, in combination with spring-supportedback-pressure bars, which are held in close proximity to the backsurface of the valve, substantially as set forth.

9. A balanced slide-valve, in combination with back-pressure bars L,springs M M, and set-screws O, substantially as set forth.

10. In a vertical engine, a steam-chest and a slide-valve therein movingvertically against a vertical seat, which valve admits steam to thecylinder at both sides of the valve, in combination with a verticalbalancing-cylinder located above said valve and a vertically-movingpiston working in said balancing-cylinder and connected to the upper endof said slide-valve, substantially as set forth, whereby thesteampressure on the under side of said piston balances the weight ofthe valve and the valvegear.

11. In a vertical engine, a valve, a balanc- ICO IIS

ing-cylinder, and apistonin said cylinder conopened, or free to open andclose said apernected to said valve, in combination with a tures,substantially as set forth. IO valve-cap on the outer end of saidcylinder, In testimony whereof I affix my signature in said cap having aseries of apertures, which presence of two witnesses.

establish communication between the upper HENRY-T. GILES. end of saidcylinder and the outer air, said Witnesses: cap being arranged to beheld with the said Jos. H. BLAOKWOOD,

apertures constantly closed or constantly] ANDREW PARKER.

